Speaking at the U.S. Chamber of Commerce's immigration reform summit, McCain (R-Ariz.) said the bill needs the full-throated support of industry to make it to President Obama’s desk.

“We need your help. We need you to inform the people you represent. We need their active support, not just passive,” McCain said. “We need all of you, we need all of the people you represent to be actively engaged in the community.”

Business groups are eager to see immigration reform enacted on Capitol Hill, but some have called for tweaks to the Senate legislation, particularly on a visa program for low-skilled workers.

McCain said the fate of the Gang of Eight’s bill will hinge, in part, on how aggressively companies lobby for it.

“There will be attacks and there will be cynicism. We have seen this movie before,” McCain said. “Frankly, the degree of activity by the business community, embodied by the Chamber of Commerce and its members, will have a tremendous amount of influence on whether we succeed or fail so we are asking for your active participation in the next few months as we go through this process. We would be very grateful.”

“We can’t give them the playing field. We have to fight back,” Graham said.

The Chamber played a key role in the creation of the Senate immigration reform bill. The group negotiated a new low-skilled worker visa program with the AFL-CIO to avoid a rerun of 2007, when disputes over the issue helped sideline immigration reform.

Tom Donohue, the Chamber’s president and CEO, on Friday said the group “will do what it takes” to see immigration legislation is enacted.

“Everybody is in the game,” Donohue said.

McCain and Graham said they are optimistic about the bill’s chances in the Senate. Both predicted the bill could receive at least 70 votes there.

They gave credit to the Chamber for their work on the Senate bill and thanked Randy Johnson, the group’s senior vice president of labor, immigration and employee benefits policy.

“I would like to pay a special thank you to Randy Johnson, who I believe his reward will be in heaven, not here on Earth, for the great job that he did,” McCain said.

Johnson helped negotiate the agreement between the Chamber and the AFL-CIO on the low-skilled worker visa program.

The immigration reform push has momentum in the Senate, but the road to final passage is fraught with danger.

The deal has come under criticism from some trade groups who argue the cap on the new visas is too low. Some lobbyists have said they will push to raise that cap, potentially upending the Gang’s carefully negotiated agreement.

In the House, meanwhile, lawmakers are working on a rival immigration plan with substantial differences from the Senate bill, including a longer pathway to citizenship and an increase in worker visas.

McCain said that the Gang of Eight will be on watch for amendments designed to take down their legislation, and will join together to stop them when needed.

“We are going to take votes that we otherwise wouldn’t to prevent the bill from being destroyed. We have that basic understanding,” McCain said.

The compromise crafted by the senators included concessions from both Democrats and Republicans. Members of the Gang are adamant that there isn’t much room to change it.

“We have very little, little maneuver room,” Graham said.

The South Carolina Republican said he is worried about how the visa programs — including the low-skilled component — could change as the bill moves forward.

“The one thing is I worry about is going after the low-skilled and high-skilled visa programs because they are hanging in balance now where it is enough, but just barely enough,” Graham said. “I hope the AFL-CIO will not be tempted to try to reduce those numbers. From our point of view, I hope we understand there’s not a whole lot of ways to improve the pathway to citizenship.”

The Gang of Eight has also had to push back against lawmakers who want to slow immigration reform after the Boston Marathon bombings. One of the bombing suspects’ names was reportedly misspelled on a travel document when he visited Russia in 2011, making him harder to track.

Graham said the Senate bill would improve national security, including an exit-entry system that would be better at tracking travelers.

“You see in Boston the inability to track someone who was on a watch list. The name was misspelled and the system could not pick it up. Under our proposal, when you leave the country and come back in on any kind of visa, you have to swipe the passport and that’s the end of the misspelling,” Graham said.

Graham said it is vital that comprehensive immigration reform pass during this Congress.

“If we fail for some reason, it will be decades before anyone else picks this back up again,” he said.